DIGESTIVE ORGANS. 31 



separated in the Culainaries, in Sepia and Sepiola; less long but 

 well separated in Ommastrephes ; but little separated in Onyeho- 

 teutbis, in Loligopsis and in Histioteuthis, wbicb at the same 

 time have a much longer, more curved and sharper rostrum. The 

 posterior expansion is short, composed of three equal lobes in 

 the Argonauts and Tremoctopus, very long and with only an 

 indication oi' a lobe in Octopus, and without lobes in Sepia, the 

 Calamaries, Rossia and all other cephalopoda. 



The rostral part of the inferior mandible is rounded behind in 

 all the octopods, slanting in the decapods. The wings are short, 

 wide in Argonauta and Tremoctopus ; very long, narrow and 

 arcuated in Octopus ; long, straight and wide in Sepia, etc.; 

 short in Onychoteuthis and Ommastrephes. The posterior ex- 

 pansion is wide, not carinated above in Argonauta and Trem- 

 octopus ; very long, narrow, carinated in Octopus ; moderately 

 long, wide, carinated above, more sloped in Sepia, Sepiola and 

 the Calamarics ; very short much carinated, strongly sloped be- 

 hind in Onychoteuthis, Ommastrephes, etc. 



Under the tongue is found a fleshy mass covered with papill*', 

 which is supposed to be the organ of taste ; and in Nautilus we 

 find similar papilhe on the tongue (behind the teeth), to its 

 entrance into the gullet. 



The fleshy tongue is tinned above with rows of recurved, 

 spinous teeth, the arrangement of which differs in the various 

 genera. Ordinarily, as in the (libra nchiates, we find the series 

 of teeth to consist each of a, central one with three side-teeth on 

 either side of it, and sometimes, as in Eledone and Loligo, an 

 additional plate on either side ; but in Nautilus we find a modi- 

 fication in live somewhat quadrangular central teeth of which the 

 middle one has the most pointed end, and on either side two 

 long fangs Avith a much smaller plate at the base of each in all 

 thirteen teeth in a series. The central teeth, which are simple in 

 Sepia and Sepiola, are tricuspid in Loligo and denticulated in 

 Eledone; whilst the lateral undni are usually claw-like. Fifty 

 rows of teeth may be found on the tongue of the Sepia ; their 

 continuous growth compensates the loss by abrasion. 



(Plates 5 and 6 exhibit the teeth of various cephalopoda.) 



The rounded, sack-like stomach which is situated towards the 

 middle or end of the body is connected with the mouth by a long 



